1. Field of the Invention
The present invention relates to mannose-containing feed which has excellent handling properties and which can be produced at low cost, and to a process for producing such feed.
2. Description of the Prior Art
Although industrial waste problems have been social issues for many years, a promising clue for solving the problems has not yet been found in spite of extensive efforts in various fields. Food wastes discharged from food processing factories are residues resulting from processes in which non-digestible and/or distasteful materials are removed from raw materials, and specific useful constituents are recovered for use. Since such residues contain protein, carbohydrate, fat, cellulose and the like, many of food wastes such as brewer's grains, bean curd refuse, bran, and crushed orange lees are currently used as feed. Many of these food wastes, however, have a drawback in that their shelf life are short because of their high water contents. Furthermore, the appreciation of the yen promotes import of cheap feed from abroad, and there is a trend for dairy farmers in Japan to rely on such imported feed which is more easy to handle.
Copra meal, a ground product of extraction residue of coconut oil, is also mostly used in Japan as feed for cattle and swine. However, copra meal as such has a drawback in that it is not suitable as feed for fowl because it contains a rather large amount of fiber and its amino acid composition is not quite acceptable ("Shiryo-No-Kiso-Chishiki", Toyo Keizai Shinpo, p. 58 (1970)).
Meanwhile, mannose has proved to have an effect on preventing harmful bacterial infection via intestinal tract, and feed which contains mannose as an ingredient for preventing infection has been proposed (Japanese Patent Publication No. H8(1996)-38064 A).
Mannose is heretofore produced by acidic or enzymatic degradation of glucomannan contained in, for example, wood or bulb of konjak or galactomannan contained in, for example, guar gum.
However, since the process for extracting various mannans from natural sources requires complicated procedures and high costs, feed which contains mannose thus produced has a drawback of being expensive. In addition, since mannose thus produced is in the form of powder or aqueous solution, it has another drawback in that it is difficult to mix mannose uniformly with feed. Furthermore, the process for extracting mannan produces a large amount of waste residue. Since this residue is not suitable for use as feed because it no longer contains useful constituents such as amino acids or sugars, it also causes additional industrial waste problems.